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  • Creating an AST node in Erlang

    - by dagda1
    Hi, I am playing about with Erlang and I am trying to write a simple arithmetic parser. I want to try and parse the following expression: ((12+3)-4) I want to parse the expression into a stack of AST nodes. When parsing this expression, I would first of all create a binary expression for the (12+3) expression which would look something like this in C#: var binaryStructure = new BinaryStructure(); binaryStructure.Left = IntegerLiteralExpression(12); binaryStructure.Right = IntegerLiteralExpression(4); binaryStructure.Operator = binaryExpression.Operator != BinaryOperatorType.Addition; I am quite new to Erlang and I am wondering how I would go about creating a structure like this in Erlang that I can place on a List that I would use as the stack of expressions. Can anyone suggest how to create such a tree like structure? Would a function be a good fit? Thanks Paul

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  • MySQL LOAD DATA LOCAL INFILE example in python?

    - by David Perron
    I am looking for a syntax definition, example, sample code, wiki, etc. for executing a LOAD DATA LOCAL INFILE command from python. I believe I can use mysqlimport as well if that is available, so any feedback (and code snippet) on which is the better route, is welcome. A Google search is not turning up much in the way of current info The goal in either case is the same: Automate loading hundreds of files with a known naming convention & date structure, into a single MySQL table. David

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  • error: gnome.h: No such file or directory

    - by michael
    I would like to resolve this 'error: gnome.h: No such file or directory ' on ubuntu. I get this error: /bin/sh: gnome-config: not found In file included from TestMDI.cpp:18: ../../../../dist/include/system_wrappers/gnome.h:3:24: error: gnome.h: No such file or directory From this: http://ubuntuforums.org/showthread.php?t=295105 I tried: $ sudo apt-get install libgnomeui-dev Reading package lists... Done Building dependency tree Reading state information... Done libgnomeui-dev is already the newest version. 0 upgraded, 0 newly installed, 0 to remove and 21 not upgraded. But that still does not resolve my problem. Any idea how to fix it?

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  • python: iif or (x ? a : b)

    - by Albert
    If Python would support the (x ? a : b) syntax from C/C++, I would write: print paid ? ("paid: " + str(paid) + " €") : "not paid" I really don't want to have an if-check and two independent prints here (because that is only an example above, in my code, it looks much more complicated and would really be stupid to have almost the same code twice). However, Python does not support this operator or any similar operator (afaik). What is the easiest/cleanest/most common way to do this? I have searched a bit and seen someone defining an iif(cond,iftrue,iffalse) function, inspired from Visual Basic. I wondered if I really have to add that code and if/why there is no such basic function in the standard library.

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  • Java Array Comparison

    - by BlairHippo
    Working within Java, let's say I have two objects that, thanks to obj.getClass().isArray(), I know are both arrays. Let's further say that I want to compare those two arrays to each other -- possibly by using Arrays.equals. Is there a graceful way to do this without resorting to a big exhaustive if/else tree to figure out which flavor of Arrays.equals needs to be used? I'm looking for something that's less of an eyesore than this: if (obj1 instanceof byte[] && obj2 instanceof byte[]) { return Arrays.equals((byte[])obj1, (byte[])obj2); } else if (obj1 instanceof boolean[] && obj2 instanceof boolean[]) { ...

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  • Convert perl one-liner into a script

    - by Stefan Lasiewski
    I find alot of perl one-liners online. Sometimes I want to convert these one-liners into a script, because otherwise I'll forget the syntax of the one-liner. For example, I'm using the following command (from nagios.com): tail -f /var/log/nagios/nagios.log | perl -pe 's/(\d+)/localtime/e' I'd to replace it with something like this: tail -f /var/log/nagios/nagios.log | ~/bin/nagiostime.pl However, I can't figure out the best way to quickly throw this stuff into a script. Does anyone have a quick way to throw these one-liners into a Bash or Perl script?

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  • bash script problem, find , mv tilde files created by gedit

    - by Ke
    Hi, im using linux with gedit which has the wonderful habit of creating a temp file with a tilde at the end for every file I edit. im trying to move all of these files at once to a different folder using the following: find . -iname “*.php~” -exec mv {} /mydir \; However, its now giving me syntax errors, as if it were searching through each file and trying to move the piece of text. I just want to move all of the files ending in .php~ to another directory. Any idea how I do that? Cheers Ke

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  • ASP.Net MVC - Build a load on demand TreeView

    - by Eric P
    I am wondering how to build a load on demand tree view using ASP.Net MVC. I understand what is involved in creating a JQuery TreeView using lists, but the load on demand part is really confusing me. I don't need the full solution, but can somebody point me in the right direction on where I should start? I have done these plenty of times using WinForms which keeps the view state preserved. One of the issues I am seeing is remembering all the node that have been expanded and not just the newly expanded one. If anyone had some advice, I would appreciate it. Thanks!

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  • optional local variables in rails partial templates: how do I get out of the (defined? foo) mess?

    - by brahn
    I've been a bad kid and used the following syntax in my partial templates to set default values for local variables if a value wasn't explicitly defined in the :locals hash when rendering the partial -- <% foo = default_value unless (defined? foo) %> This seemed to work fine until recently, when (for no reason I could discern) non-passed variables started behaving as if they had been defined to nil (rather than undefined). As has been pointed by various helpful people on SO, http://api.rubyonrails.org/classes/ActionView/Base.html says not to use defined? foo and instead to use local_assigns.has_key? :foo I'm trying to amend my ways, but that means changing a lot of templates. Can/should I just charge ahead and make this change in all the templates? Is there any trickiness I need to watch for? How diligently do I need to test each one?

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  • NetBeans Web-Services Client Project - repeated WSDL parsing

    - by RedGrittyBrick
    I created a new project thus ... File, New Project... Java, Java Application. Right-click project icon in "Projects" tree-view panel. Choose New, Web Service Client... Specify WSDL file e.g. ( ) Project (*) Local file D:\temp\Foo\Bar.wsdl ( ) WSDL URL [Set Proxy...] client-style JAX-WS [ ] Generate Dispatch code It parsed the WSDL and generated lots of java files. I created a main class and used Netbeans to insert a WS client call Now whenever I run my code (Desktop app), it again parses the WSDL (which doesn't ever change) and regenerates about 78 java files and compiles them. How do I stop Netbeans performing this uneccessary and time-consuming action?

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  • Where do you take mocking - immediate dependencies, or do you grow the boundaries...?

    - by Peter Mounce
    So, I'm reasonably new to both unit testing and mocking in C# and .NET; I'm using xUnit.net and Rhino Mocks respectively. I'm a convert, and I'm focussing on writing behaviour specifications, I guess, instead of being purely TDD. Bah, semantics; I want an automated safety net to work above, essentially. A thought struck me though. I get programming against interfaces, and the benefits as far as breaking apart dependencies goes there. Sold. However, in my behaviour verification suite (aka unit tests ;-) ), I'm asserting behaviour one interface at a time. As in, one implementation of an interface at a time, with all of its dependencies mocked out and expectations set up. The approach seems to be that if we verify that a class behaves as it should against its collaborating dependencies, and in turn relies on each of those collaborating dependencies to have signed that same quality contract, we're golden. Seems reasonable enough. Back to the thought, though. Is there any value in semi-integration tests, where a test-fixture is asserting against a unit of concrete implementations that are wired together, and we're testing its internal behaviour against mocked dependencies? I just re-read that and I think I could probably have worded it better. Obviously, there's going to be a certain amount of "well, if it adds value for you, keep doing it", I suppose - but has anyone else thought about doing that, and reaped benefits from it outweighing the costs?

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  • using indexer to retrieve Linq to SQL object from datastore

    - by fearofawhackplanet
    class UserDatastore : IUserDatastore { ... public IUser this[Guid userId] { get { User user = (from u in _dataContext.Users where u.Id == userId select u).FirstOrDefault(); return user; } } ... } One of the developers in our team is arguing that an indexer in the above situation is not appropriate and that a GetUser(Guid id) method should be prefered. The arguments being that: 1) We aren't indexing into an in-memory collection, the indexer is basically performing a hidden SQL query 2) Using a Guid in an indexer is bad (FxCop flagged this also) 3) Returning null from an indexer isn't normal behaviour 4) An API user generally wouldn't expect any of this behaviour I agree to an extent with (most of) these points. But I'm also inclined to argue that one of the characteristics of Linq is to abstract the database access to make it appear that you're simply working with a bunch of collections, even though the lazy evaluation paradigm means those collections aren't evaluated until you run a query over them. It doesn't seem inconsistent to me to access the datastore in the same manner as if it was a concrete in-memory collection here. Also bearing in mind this is an inherited codebase which uses this pattern extensively and consistently, is it worth the refactoring? I accept that it might have been better to use a Get method from the start, but I'm not yet convinced that it's completely incorrect to be using an indexer. I'd be interested to hear all opinions, thanks.

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  • Django and mod_python config

    - by Peter
    My Django project is placed in /www/host1/htdocs/my/project, www and my are links to other actual folders. Apache has mod_python enabled. I have a .htaccess in project folder: SetHandler python-program PythonHandler django.core.handlers.modpython SetEnv DJANGO_SETTINGS_MODULE project.settings PythonDebug On PythonOption django.root /my/project PythonPath "['/www/host1/htdocs/my/project'] + sys.path" I suppose my site should be accessible from http://host1/my/project, but I see the following error: ImportError: Could not import settings 'project.settings' (Is it on sys.path? Does it have syntax errors?): No module named project.settings Can somebody give any suggestions?

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  • How do I access variables with hyphenated names in Smarty?

    - by abeger
    I've got a PHP page that parses an XML file with SimpleXml, then passes that object to a Smarty template. My problem is that the XML file has hyphens in its tag names, e.g. video-player. In PHP, this is no problem, I just use $xml->{'video-player'} and everything's fine. Smarty, on the other hand, throws a fit when I try to use that syntax. The only solution I've come up with so far is to use a variable to store the name, e.g., { assign var=name value="video-player" } { $xml->$name } But this isn't terribly graceful to say the least. Is there another, better, approach to referring to a hyphenated variable name in Smarty?

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  • Rails Custom Plugin/Gem with Partials

    - by Jason
    I am writing a gem which provides helpers for views. The HTML I want to insert via the helper is complex enough that I'd rather write it in a _partial.html.erb file. How do I get the gem's view path include in the application's load_path? Note: the only gem I've found that does something like this is Devise. When a view cannot be found, Rails prints the load path which (on my machine) looks like: Missing partial sortable_nested_set/tree with {:handlers=>[:erb, :rjs, :builder, :rhtml, :rxml], :formats=>[:html], :locale=>[:en, :en]} in view paths "/home/jason/VirtualRestaurant3/app/views", "/home/jason/.rvm/gems/ruby-1.9.2-preview3/gems/devise-1.1.rc0/app/views" How does Devise do it? My gem: http://github.com/jrmurad/SortableNestedSet Devise gem: +http://+github.com/plataformatec/devise

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  • LIKE operator with $variable

    - by skarama
    This is my first question here and I hope it is simple enough to get a quick answer! Basically, I have the following code: $variable = curPageURL(); $query = 'SELECT * FROM `tablename` WHERE `columnname` LIKE '$variable' ; If I echo the $variable, it prints the current page's url( which is a javascript on my page) Ultimately, what I want, is to be able to make a search for which the search-term is the current page's url, with wildcards before and after. I am not sure if this is possible at all, or if I simply have a syntax error, because I get no errors, simply no result! I tried : $query = 'SELECT * FROM `tablename` WHERE `columnname` LIKE '"echo $variable" ' ; But again, I'm probably missing or using a misplaced ' " ; etc. Please tell me what I'm doing wrong!

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  • database design question

    - by Leonardo
    Hi all, I am building a database as a simple exercise, it could be hosted on any database server, so I am trying to keep things as much standard as possible. Basically what I would like to do is a 'code' table that get referenced by other entities. I explain: xcode id code r role p property code r admin r staff p title .... then I would like to have some view like: role (select * from code where xcode='r') r admin r staff property (select * from code where xcode='p') p title then, suppose we have an entity myentity id - 1 role - admin (foreign key to role) title - title (foreign key to property) Obviously I cannot create foreign key to a view, but this is to tell the idea I have in mind. How can I reflect such behaviour using whenever possible, standard sql syntax, then as a second option, database additional features like trigger ecc... ? Because if I tell that role and title in myentity are foreign key to 'code', instead of the views, nothing would stop me to insert a role in title field. thanks Leonardo

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  • Fossil gpg workflow for teams

    - by Alex_coder
    I'm learning fossil and trying to reproduce a workflow for two people modifying the same source code tree. So, Alice and Bob both have local repositories of some source code. Both have autosync off. Alice hacks some more, does some commits signing check-ins with her gpg key. This part is fine, as Alice I've managed to generate gpg keys, fossil asked me the key password when commiting. I'm also aware of gpg-agent but don't use it yet, because I'm trying to keep things as simple as possible for now. Now, at some point Bob pulls changes from Alice's fossil repo. How would he verify Alice's signed check-ins?

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  • Infix to Postfix and unary/binary operators

    - by Jaapjan
    I have a piece of code that converts an infix expression to an expression tree in memory. This works just fine. There's just one small trouble. I just connect work out how to involve the unary operators correctly (the right associative ones). With the following infix expression : +1 + +2 - -3 - -4 I would expect an RPN of: 1+2++3-4-- Yet, none of the online infix-post converters I can find handle this example in the way I would expect. Does anyone have a clear explanation of handling right associative operators, specifically the binary ones that can be mistaken for the unary ones?

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  • Setting column length of a Long value with JPA annotations

    - by Gearóid
    Hi, I'm performing a little database optimisation at the moment and would like to set the column lengths in my table through JPA. So far I have no problem setting the String (varchar) lengths using JPA as follows: @Column(unique=true, nullable=false, length=99) public String getEmail() { return email; } However, when I want to do the same for a column which is of type Long (bigint), it doesn't work. For example, if I write: @Id @Column(length=7) @GeneratedValue(strategy = GenerationType.AUTO) public Long getId() { return id; } The column size is still set as the default of 20. Are we able to set these lengths in JPA or am I barking up the wrong tree? Thanks, Gearoid.

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  • Rails equivalent of respond_to |format| with a straight render

    - by brad
    I'm working with ActiveResource a lot so my service models are only using XML. Thus, I have no need for a respond_to block, I literally just render :xml => @model I can't however figure out how to render a 404 header using this. I've had to resort to respond_to, which I think adds a few unnecessary method calls. Here's what I'm using: respond_to do |format| if (record_found) render :xml => @some_record else format.xml{ head :not_found } end end but I just want something like render :xml => head :not_found which doesn't work. Can anyone tell me the proper syntax?

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  • Problem wit MDAC when trying to compile in VS2008 using x64 bit target platform

    - by grobartn
    I am trying to compile an 32 bit application. I am aware of problems with it but that is why its being compiled on 64 bit version. I am hanging at this problem. Application uses lots of sql stuff. In sqltypes.h file: (provided by MDAC) #ifdef _WIN64 typedef INT64 SQLLEN; typedef UINT64 SQLULEN; typedef UINT64 SQLSETPOSIROW; #else For some reason when its compiled on 32 bit platform it works great But when I try building it on 64 it goes berserk. Error 61 error C2146: syntax error : missing ';' before identifier 'SQLLEN' ..\external\microsoft sdk\include\sqltypes.h 50 It does not recognize INT64, UINT64. Is there something I need to enable so it will work under 64 build process? Missing some #include or #define? Any help would be great Thanks

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  • How can I improve this design?

    - by klausbyskov
    Let's assume that our system can perform actions, and that an action requires some parameters to do its work. I have defined the following base class for all actions (simplified for your reading pleasure): public abstract class BaseBusinessAction<TActionParameters> : where TActionParameters : IActionParameters { protected BaseBusinessAction(TActionParameters actionParameters) { if (actionParameters == null) throw new ArgumentNullException("actionParameters"); this.Parameters = actionParameters; if (!ParametersAreValid()) throw new ArgumentException("Valid parameters must be supplied", "actionParameters"); } protected TActionParameters Parameters { get; private set; } protected abstract bool ParametersAreValid(); public void CommonMethod() { ... } } Only a concrete implementation of BaseBusinessAction knows how to validate that the parameters passed to it are valid, and therefore the ParametersAreValid is an abstract function. However, I want the base class constructor to enforce that the parameters passed are always valid, so I've added a call to ParametersAreValid to the constructor and I throw an exception when the function returns false. So far so good, right? Well, no. Code analysis is telling me to "not call overridable methods in constructors" which actually makes a lot of sense because when the base class's constructor is called the child class's constructor has not yet been called, and therefore the ParametersAreValid method may not have access to some critical member variable that the child class's constructor would set. So the question is this: How do I improve this design? Do I add a Func<bool, TActionParameters> parameter to the base class constructor? If I did: public class MyAction<MyParameters> { public MyAction(MyParameters actionParameters, bool something) : base(actionParameters, ValidateIt) { this.something = something; } private bool something; public static bool ValidateIt() { return something; } } This would work because ValidateIt is static, but I don't know... Is there a better way? Comments are very welcome.

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  • Iterate through a DataTable to find elements in a List object?

    - by Darth Continent
    As I iterate through a DataTable object, I need to check each of its DataRow objects against the items in a generic string List. I found a blog post using the List's Find method along with a delegate, but whereas that example has a separate class (Person), I'm attempting something like the following using an instance of the string object: // My definition of the List object. List<string> lstAccountNumbers = new List<string>(); ... // I populate the List via its Add method. ... foreach (DataRow drCurrentRow in dtMyDataTable.Rows) { if (lstAccounts.Find(delegate(string sAccountNumber) { return sAccountNumber == drCurrentRow["AccountNumber"]; }) { Found_DoSomething(); } else { NotFound_DoSomethingElse(); } } However, with this syntax I'm receiving "Cannot implicitly convert type 'string' to 'bool'" for the if block. Could someone please clarify what I'm doing wrong and how best to accomplish what I'm trying to do?

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  • Eclipse and Actionscript 3

    - by teapot7
    Does anyone know of any good solutions (Eclipse plugins presumably) for using Eclipse to develop in ActionScript 3? There are a number of solutions for developing with ActionScript 2, leveraging MTASC, Swfmill and other open source tools, but I'm specifically looking for AS3 support. It's simple enough to use Eclipse as an editor, and a place from which to invoke Ant scripts to compile with the Adobe command line tools, but I'm looking for syntax colouring, autocompletion, refactoring, debugging - all the modern IDE luxuries. Other tool I've used: FlashDevelop: free and good, but Windows only and doesn't have refactoring. Nevertheless a nice piece of work. IntelliJ Idea: very nice ActionScript 3 support, though not quite as slick as their Java support. Unfortunately AS3 is not supported in the free/community edition of Idea and I'm not ready to purchase the full version as yet.

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